DUBLIN — Hundreds of thousands of people braved wet and windy weather to attend Pope Francis’ Mass at Phoenix Park in Dublin on Sunday, while thousands more gathered in the city center for protests against clerical sexual abuse amid fresh reports the Pontiff ignored allegations stretching back years.

“We ask forgiveness for the abuses in Ireland,” said Pope Francis at the Mass, listing a litany of abuses including clerical sex crimes, a lack of compassion and action by church leaders and the separation of single mothers and children in industrial laundries.

“We ask forgiveness for all the times that we, as the church, did not provide survivors of any kind of abuse compassion, to look for justice, and the truth, and concrete actions, so we ask forgiveness,” Pope Francis said at the Mass, which was expected to attract over 500,000 people and concludes his two-day visit to Ireland.

The visit coincides with the World Meeting of Families, a gathering of the Catholic Church that was thrown into chaos last week by a Pennsylvania grand jury report detailing decades of sexual abuse and cover-ups by clerics.

On Sunday, Pope Francis faced calls for his resignation from the former Vatican ambassador to Washington, Carlo Maria Vigano, who said in a letter that he told the Pontiff about allegations of sexual abuse against the prominent Cardinal Theodore McCarrick back in 2013. Vigano said the Pontiff did nothing about it.

A source close to Vigano confirmed the letter is genuine. CNN has so far not received a response from the Vatican.

McCarrick, 88, who once led the Archdiocese of Washington and was a force in American politics, resigned last month after a decades-old allegation of sexual abuse of a teenage altar boy.

Earlier in the day, the Pontiff begged “the Lord’s forgiveness” for clerical sexual abuse, during a visit to the Knock Sanctuary, a Catholic pilgrimage site where villagers say they witnessed an apparition of the Virgin Mary in 1879.

“None of us can fail to be moved by the stories of minors who suffered abuse, were robbed of their innocence and left scarred by painful memories,” Francis said during a speech at the Sanctuary.

As thousands of people filled Phoenix Park for Sunday Mass, large crowds also gathered in Dublin City center for a “Stand for Truth” solidarity event, organized by Colm O’Gorman, an abuse survivor who is now executive director of Amnesty International.

Varadkar, the country’s first openly gay leader, said the time had come “for us to build a new, more mature relationship between church and state in Ireland — a new covenant for the 21st century.”

It’s a very different reception — and a very different Ireland — to the last papal visit in 1979, when Pope John Paul II was greeted like a rock star in Phoenix Park by nearly one-third of the country’s population.

“The church’s hold on public life in Ireland has fundamentally changed since ’79,” John Allen, who has written multiple books on the Vatican, told CNN.

In the nearly four decades that have elapsed, Ireland has become a far less Catholic country both socially and legally. Irish voters have struck down bans on divorce, same-sex marriage and, most recently, abortion. And Ireland’s church attendance has waned from 90% to about 30% as revelations of abuse by Catholic-run institutions continue to damage its moral authority and diminish its influence.

Catholic Ireland at a crossroad?

More than 10,000 people also joined the Facebook event “Say Nope to the Pope,” a campaign calling on protesters to snap up tickets to Mass and then not show up. Another 9,000 signed up for a “Stand for Truth” solidarity event. And as the Pope addresses the faithful at 3 p.m., a silent vigil was set to take p place in the town of Tuam, where 800 children’s bodies were discovered last year at a former Catholic church mother-and-baby home.

Some local leaders boycotted a formal reception with the Pope, too. Orla O’Connor, director of the National Women’s Council of Ireland, said she declined an invitation to join the Pope and representatives of civil society on Saturday in protest over the “trauma” that the Church has caused women, especially in blocking rights and equality.

But even so, Ireland remains a country where 78% of men and women still check the “Catholic” box. All tickets were swept up to see Pope Francis on Sunday at the Shrine of Our Lady of Knock in County Mayo.

“It’s something of a paradox. We’re at a stage where we consider ourselves a post-Catholic society, but people can’t stop talking about Catholicism,” Eamon Maher, co-editor of “Tracing the Cultural Legacy of Irish Catholicism,” told CNN. “It’s still a defining feature of what makes the Irish, Irish.”

Two American cardinals dropped out of the World Meeting of Families as a result of the report, including Cardinal Donald Wuerl, the former Bishop of Pittsburgh and a key papal ally. Weurl, who was accused of helping to cover up abusive behavior, was to deliver the keynote address on “the welfare of the family.” In the wake of the report, the bishop said he “did everything that I possibly could” to stop abuse from happening.

In response to rising anger over the revelations, the Pope issued a letter on Monday acknowledging the church’s failure to act over abuse, but the apology has been criticized by victims — as well as Irish clergy members — for not going far enough.

And after the Archbishop of Dublin, Diarmuid Martin, sparked outrage earlier this month when he indicated that time would be “very tight” for the Pope to meet with abuse survivors on his two-day visit, the Vatican broke with tradition by confirming that private meetings would indeed take place.

“I am disgusted with Pope Francis, and utterly repulsed with how the Vatican has conducted itself in relation to this meeting,” O’Gorman told CNN. “In terms of what needs to be addressed, it is of no value.”